Dual-band wavelength-comb-swept laser to extend displacement measurement range

We demonstrate dual-band wavelength-comb-swept laser for solving the aliasing interferometer signal in displacement measurement. Wavelength-comb-swept laser with etalon filter has longer coherence length and narrower linewidth than conventional wavelength-swept laser. On the other hand, aliasing of interferometer signal in displacement measurement is induced because of discrete distribution of comb spectra in wavelength domain. By using the dual-band wavelength-comb-swept-laser which has two different free spectral range (FSR) comb in each band, aliasing interferometer signal can be solved.